The corrective services commissioner in Western Australia says authorities don't know what caused juveniles to riot last night, causing a major emergency. Dozens of prisoners at the Banksia Hill Detention Centre were involved in the riot, the worst such incident in WA's prison system in years.

Transcript

SALLY SARA: Western Australia's juvenile justice system is under question, after a riot overnight at the state's only detention centre for young offenders.

Police, fire crews and the police helicopter were called in to deal with the emergency at the Banksia Hill facility.

More than 70 young detainees involved in the incident have been transferred to an adult prison.

Corrective Services officials are trying establish what caused the unrest and child advocates are concerned about the safety of young people behind bars.

David Weber reports.

DAVID WEBER: The disturbance started at about half-past-six.

Three detainees got on the roof of the Banksia Hill Detention Centre in Canning Vale. They were joined by dozens of others.

The corrective services commissioner, Ian Johnson.

IAN JOHNSON: Around about 60 police attended; our emergency support group. But there is a concern that the people on the roof and the others who joined them were then able to compromise other cells and release other detainees.

I don't want people to think we're talking about 10-year-olds here, we look after people from the age of 10 to 18. Some of these people are big, fit young men who have a history of violence.

DAVID WEBER: Commissioner Johnson says they armed themselves, using rocks and glass as makeshift weapons.

He says there was considerable damage to cells.

IAN JOHNSON: My initial indications are that it's in the vicinity of 90. Now as to what extent that damage is for the 90, it could be just the someone smashed up their bunk bed, as opposed to more significant damage. But there certainly is at least 90 cells I understand have been damaged.

DAVID WEBER: Commissioner Johnson says he doesn't know if the disturbance was organised or spontaneous.

He says he doesn't think there was a particular grievance.

IAN JOHNSON: I thought about this and I think if, you know, and your listeners think about what typically happens every weekend here in Perth with the out-of-control parties, then if you could just picture the fact that we have some-206 young people and some are young and some are young men who are obviously not well behaved.

We have them 24 by seven days a week. So therefore, what you see on the weekend, these out-of-control parties, then these things are typically end up being spontaneous, then they gather momentum.

DAVID WEBER: The officers at Banksia Hill detention centre are represented by the CPSU (Community and Public Sector Union).

The state secretary, Toni Walkington.

TONI WALKINGTON: Staff retreated to a safe place which is of course what they ought to have done. The assistance of police and the emergency support group were called and within two to three hours, the centre was back under control.

DAVID WEBER: Is there any idea as to what caused it?

TONI WALKINGTON: Look, we certainly think this situation has been building for some time. Firstly, you only have one detention centre now, which means there's no flexibility to manage detainees. You've got an overcrowded situation where there are far too many detainees for both facilities and the staff ratios.

So, you've got the hot weather building and you've got detainees who have had periods of time where they've been locked down because of the lack of staffing and so you've got a pressure cooker situation occurring with tension mounting.

DAVID WEBER: More than 70 juvenile detainees have been transferred to Hakea Prison. They'll be kept separate from the adults there.

But John Welch of the WA Prison Officers Union says his members will be facing extra challenges.

JOHN WELCH: Really you shouldn't be moving juvenile prisoners into a major maximum security adult facility. It's bad practice, but that's going to create a whole range of issue for us. Last week, the Office of the Inspector of Custodial Services in their report into Hakea found that the prison was overcrowded and short-staffed and into the middle of that, what we're now going to do is put another 73 juvenile prisoners with all of the complexities that that will bring.

DAVID WEBER: John Welch says the current situation is the result of a failure to plan ahead.